Add composer 1.10.0-RC, remove composer 1.9.3
Add composer 1.10.0-RC, remove composer 1.9.3

for stack(s) cflinuxfs3 [#171279701]

cloudfoundry/php-buildpack,cloudfoundry/php-buildpack,cloudfoundry/php-buildpack,cloudfoundry/php-buildpack,cloudfoundry/php-buildpack,cloudfoundry/php-buildpack,cloudfoundry/php-buildpack